1. Field of the Invention
The present invention relates to a circuit breaker, and more particularly to a circuit breaker on a pushbutton switch having a pushbutton pivotally mounted on the pushbutton switch to ensure a power disconnection in the circuitry when there is an overload.
2. Description of Related Art
The conventional circuit breaker uses a fuse between the switch and the circuit such that when there is an electrical overload, the fuse will first melt before the overload causes damage. However, when the fuse dimension is not proper to adapt to the voltage in the circuit, an electrical overload in the circuit will not melt the fuse and still causes disaster. Therefore, different measures are employed to ensure power cut-off in a dangerous situation. For example, U.S. Pat. Nos. 5,262,748; 4,167,720; 4,937,548; 5,223,813; 5,451,729 and 5,558,211 disclose circuit breakers of different types. Although the teachings of these patents are capable to automatically cause a temporary power outage, they still suffer problems, including:
(1) Too many elements: Because there are too many elements in the circuit breaker, the movement of the elements inside the circuit breaker is complex and complicated, which causes the manufacture cost high.
(2) Not real time movement of element: Because the number of elements, when there is an electrical overload in the circuit, sometimes, a heat sensitive plate usually used in the circuit breaker is not able to work properly to cause a temporary power outage. That is, normally the heat sensitive plate will curve toward a direction away from engagement with the contact to cause a temporary power outage. However, if the heat sensitive plate is not able to disengage with the contact in time or completely, the circuit will become overheat and thus a disaster happens.
The curvature movement of the heat sensitive plate to disengage with the contact while the temperature of the heat sensitive plate is over a predetermined temperature and the curvature movement of the heat sensitive plate to engage with the contact while the temperature of the heat sensitive plate is lower than the predetermined temperature often cause sparks, which easily causes a fire and malfunction to the electronic devices.
To overcome the shortcomings, the present invention intends to provide an improved circuit breaker to mitigate the aforementioned problems.